To qualify for the list the characters must be known in their fictional stories and by their audiences for being rich.

"Net worth estimates are based on an analysis of the fictional character's source material, and where possible, valued against known real-world commodity and share price movements," Forbes said.

While the list, which Forbes editors have compiled since 2005, is all in fun, the process and resultant numbers are serious business, said special projects executive editor Michael Noer.

"We go to great lengths to calculate their net worth," Noer said. "It's similar to how we calculate real billionaires."

Market forces, especially commodities, also provided some guidance.

"McDuck was up over 30 percent, which is what gold has done this year, and his wealth is mostly in gold," Noer explained.

Similarly Jed Clampett, the country bumpkin who found black gold in the television series "The Beverly Hillbillies" benefited from rising oil prices for a $9.5 billion net worth.

Mr. Monopoly, the top-hatted, mustachioed character from the popular board game, placed ninth with $2.6 billion. The editors based his worth on the current value of Atlantic City real estate and a presumed percentage of property ownership.

The full list, with character profiles and sources of their wealth, can be found here.